xuYY8ZYc

1package sample.logic;
2
3import javax.crypto.KeyGenerator;
4import javax.crypto.SecretKey;
5import java.io.FileInputStream;
6import java.io.FileOutputStream;
7import java.io.IOException;
8import java.security.KeyStore;
9import java.security.KeyStoreException;
10import java.security.NoSuchAlgorithmException;
11import java.security.UnrecoverableKeyException;
12import java.security.cert.CertificateException;
13
14class KeyLoader {
15
16    private static final String KEYSTORE_TYPE = "JCEKS";
17    private static final String KEYSTORE_NAME = "KeyStore";
18    private static final String SECRET_KEY_NAME = "secretKeyAlias";
19    private static final String KEYSTORE_PWD = "password";
20
21    static SecretKey getKey(String algorithm) throws SecretKeyException{
22
23        SecretKey key = loadKey();
24
25        if (key == null){
26            try {
27                key = KeyGenerator.getInstance(algorithm).generateKey();
28            } catch (NoSuchAlgorithmException e) {
29                throw new SecretKeyException();
30            }
31            try {
32                storeKey(key);
33            } catch (KeyStoreException | CertificateException | NoSuchAlgorithmException | IOException e) {
34                throw new SecretKeyException();
35            }
36        }
37
38        return key;
39    }
40
41    private static void storeKey(SecretKey secretKey) throws KeyStoreException, CertificateException, NoSuchAlgorithmException, IOException {
42
43        KeyStore ks = KeyStore.getInstance(KEYSTORE_TYPE);
44        ks.load(null, KEYSTORE_PWD.toCharArray());
45
46        KeyStore.ProtectionParameter protParam = new KeyStore.PasswordProtection(KEYSTORE_PWD.toCharArray());
47        KeyStore.SecretKeyEntry skEntry = new KeyStore.SecretKeyEntry(secretKey);
48        ks.setEntry(SECRET_KEY_NAME, skEntry, protParam);
49        try (FileOutputStream fos = new FileOutputStream(KEYSTORE_NAME)) {
50            ks.store(fos, KEYSTORE_PWD.toCharArray());
51        } catch (Exception asd) {
52            System.out.println(asd.getMessage());
53        }
54    }
55
56    private static SecretKey loadKey()  {
57        KeyStore ks = null;
58        try {
59            ks = KeyStore.getInstance(KEYSTORE_TYPE);
60            ks.load(new FileInputStream(KEYSTORE_NAME), KEYSTORE_PWD.toCharArray());
61        }
62
63        catch (KeyStoreException | CertificateException | NoSuchAlgorithmException | IOException e) {
64            System.out.println(e.getMessage());
65            return null;
66        }
67        try {
68            return (SecretKey) ks.getKey(SECRET_KEY_NAME, KEYSTORE_PWD.toCharArray());
69        } catch (KeyStoreException | NoSuchAlgorithmException | UnrecoverableKeyException e) {
70            System.out.println(e.getMessage());
71            return null;
72        }
73    }
74
75
76}